Which is/are the correct order/s of atomic radius?

Options

A. `Mn gt Fe gt CO`
B. `Mn ~~ Fe ~~ Co`
C. `Sc gt Ti gt V`
D. `Zn lt Cu lt Ni`

Answer

To determine the correct order of atomic radius for the given d-block elements, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the d-block Elements**: The d-block elements in the periodic table include Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), and Zinc (Zn).

2. **Understand the Trend in Atomic Radius**:
- Atomic radius generally decreases across a period due to increasing nuclear charge, which pulls the electrons closer to the nucleus.
- In the case of d-block elements, the trend is slightly different due to the presence of d-electrons.

3. **Analyze the Atomic Radius Trend**:
- From Scandium (Sc) to Manganese (Mn), the atomic radius decreases because the nuclear charge increases without a significant increase in shielding.
- From Iron (Fe) to Nickel (Ni), the atomic radius remains approximately the same due to the shielding effect of the d-electrons.
- From Nickel (Ni) to Zinc (Zn), the atomic radius increases slightly because the shielding effect becomes more pronounced as the d-orbitals are fully filled.

4. **Evaluate the Given Options**:
- **Option 1**: Manganese (Mn) > Iron (Fe) > Cobalt (Co) - This is incorrect as Fe and Co have similar atomic radii.
- **Option 2**: Iron (Fe) ≈ Cobalt (Co) - This is correct as their atomic radii are nearly the same.
- **Option 3**: Scandium (Sc) > Titanium (Ti) > Vanadium (V) - This is correct as the atomic radius decreases from Sc to V.
- **Option 4**: Zinc (Zn) < Nickel (Ni) - This is incorrect as the atomic radius increases from Ni to Zn.

5. **Conclusion**: The correct orders of atomic radius are given in options 2 and 3.

### Final Answer:
The correct orders of atomic radius are:
- Option 2: Iron (Fe) ≈ Cobalt (Co)
- Option 3: Scandium (Sc) > Titanium (Ti) > Vanadium (V)